Gaseous electric discharge lamp device



V Jl lly 23, 1935.

M. PIRANI ET AL' 2,009,203

INVENTORS AT ORNEY Patented July 23, 1935 UNITED STATES PATENT OFFICE GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Marcello Pirani, Berlin-Wilmersdorf,

Martin In Germany June 27, 1933 Application June 12, 1934, Serial No. 730,334

5 Claims.

The present invention relates to gaseous electric discharge lamp devices.

In many types of gaseous electric discharge devices, particularly those comprising a container having thermionic electrodes and a gaseous atmosphere therein comprising a metal vapor, which container is at an elevated temperature during the operation of the device, it is de sirable to reduce the heat losses therefrom to a minimum during the operation of the device in order that the device may operate at its maximum efiiciency. Double walled containers having the space between the walls thereof evacuated are useful for this purpose.

The object of the present invention is to provide animproved and simple structure for gaseous electric discharge devices of the above type whereby heat losses from walls of the container are minimized. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description.

In accordance with this object the invention comprises a tubular container, a tubular envelope enclosing said container and an open-ended, hollow cylinder interposed between said container and said envelope. The envelope is evacuated as completely as possible. The cylinder prevents the gas molecules which remain in some quantity in the envelope even after evacuation thereof, or which are freed from the walls of the container or the envelope during the operation of the device, from travelling from the container to the envelope and thus prevents the conduction of heat from said container to said envelope. The cylinder acts as a bafiie and the gas atoms travel back and forth between the container and the cylinder and thus do not transfer their heat to the envelope. The small quantity of gas molecules which escape from the open ends of the cylinder have no practical effect on the operation of the lamp device. The container and the cylinder are supported in the envelope by flexible, mechanical means, such as coiled springs interposed between said elements, so that fused joints between these three elements of the device are avoided. Such fused joints are difiicult and expensive to make in this type of device due to the uneven expansion and contraction of each of the elements with respect to the other elements thereof caused by unequal heating of these elements during the operation of the device. When desired the intermediate cylinder is of light transmitting, flexible material, such as mica, to bviate the danger of breaking during the transportation and use of the lamp device. A thin film or dust-like coating of light transmitting, heat absorbing material is applied to the cylinder to reduce the radiation of heat therefrom, when desired. 7

In the drawing accompanying and forming part of this specification an embodiment of the invention is shown in a front elevational, partly sectional view.

Referring to the drawing the new and novel gaseous electric discharge lamp device comprises a container I having an electrode I2 sealed therein at each end thereof and a gaseous filling therein, such as a rare gas, a gas mixture, a metal vapor, a mixture of metal vapors, or, a mixture of gas and metal vapor, such as a mixture of neon or argon and sodium vapor, or a mixture of argon and mercury vapor. Said electrodes I2 consist of a curved bar or rod of electron emitting material, such as barium oxide, and a metal filament, such as a tungsten filament, wrapped around said bar. Said container I is enclosed by an envelope 2 which is evacuated to a high degree. Said envelope 2 has a base 3 cemented to each end thereof and each of said bases 3 is provided with a pair of contact-pins 4 and 5. Current leads 8 and 9 are attached to said contact pins 4 and 5 respectively and are sealed into the pinched part 6 of the stem I of said envelope 2. The thinner end parts of said current leads 8 and 9 are sealed into the thickened parts I0 and II respectively of the container I. The portion of each of said leads 8 and 9 between the pinch part 6 of the stem I and the parts I0 and I I of the container I are coiled to make them flexible so that said container I and said envelope 2 can expand and contract freelyand at different rates without rupturing said leads 8 and 9 or fracturing said container I or said envelope 2. The ends of said current leads 8 and 9 in said container I are attached to the ends of the filament of said electrode I2.

A hollow cylinder I3, open at both ends, surrounds the container I and is, of course, slightly larger in diameter than said container I. Said cylinder I3 is of light transmitting material such as glass, quartz or mica. Said cylinder I3 is supported by a coiled spring I4 at each end thereof which presses against the outer wall of said 50 container I and the inner wall of said cylinder I3. Said container I is supported in said envelope 2 by a spring I5 at each end thereof which is held in position by a pair of circular indentations I! in the wall of said envelope 2 to prevent 55 ll in position in said envelope 2.

movement thereof along the length of said envelope 2. Said spring [5 presses against the inner wall of said envelope'2 and the outer wall of said container-l at the shoulder l6 thereof and the end of the cylinder I3 rests against said spring l5 which keeps said cylinder 1 3 and springs The container I, and the cylinder l3 are thus firmly but flexibly supported and spaced apart in said envelope 2 so that the lamp device can be transported and used without danger of breakage and all 01 said elements, I,- 2 and I3 can expand and contract at different rates during the operation of the device without fracturing the walls thereof,

Said cylinder l3 has a very thin coating or deposit l8 thereon of a material which transmits the visible light emitted by the gaseous filling in said container I when said gaseous filling is excited to luminescence by the passage of an electric discharge between said electrodes li but which absorbs the infra-red or heat rays emitted by said gaseous filling. A thin film or dust-like coating or deposit of gold or silver is suitable for the body I8 and such material is applied to the cylinder l3 by methods well known in the art, as by chemical deposition, or cathode sputtering. The cylinder l3 consists of a transparent, a translucent, or a colored glass, when desired or said cylinder l3 consists of a fluorescent or heat absorbing glass, when desired.

While we haveshown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for examp e, the cylinder I3 is braced against the inner wal of the envelope 2 instead of the outer wall of the container 2, when desired, or said cylinder I3 is braced against both of said walls, when desired, and other types. of electron emitting electrodes are used, when desired.

What we claim as new and desire to secure by Letters Patent of the United States is:--

2 amazes 1. A gaseous electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, an envelope for said container, 9, baiiie interposedbetween said con-. tainer and said envelope, resilient support means for said container and said baflie in said en velope, said baflie being a filter for the rays emitted by the discharge in said device. H 2; A gaseous electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, an envelope for said container, a battle interposed between said container and said envelope, flexible support means for said container and said baflie in said envelope, said support means spacing apart said container, said baflie and said envelope, that part of the electrode leads between said envelope and said container being flexible.

3. A gaseous electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, an envelope for said container a baflle interposed between said container and said envelope, resilient support means for said container and said baflie in said envelope,

said baflle being of light transmitting, heat ab-.

sorbing material.

4. A gaseous electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, an envelope for said container, a baflie interposed between said container and said envelope, resilient support means for said container and said baflle in said envelope, said baflie comprising luminescent material.

5. A gaseous electric discharge lamp comprising a tubular container, a gaseous atmosphere therein, electrodes sealed therein, a tubular envelope for said container, an open-ended tubular baffle interposed between said container and said envelope and resilient means for supporting and spacing apart said container and said baflie in said envelope.

' MARCELLOPIRANI.

MARTIN REGER. ADOLF FEHSE. 

